Tried upgrading a smart contract through Defender on Moonbase. It approved the tx just fine, however, when clicked the execute button it gave "Transaction would revert. Check that permissions, balances, and other function requirements are valid for the transaction you want to run.". The wallets had enough gas token DEV. When tried to reject the tx, it gave the same error, so it was not possible to discard the tx at all. Executing the same pre-approved through defender tx on https://multisig.moonbeam.network/ worked just fine without any revert.
Code to reproduce